1. Field of the Invention
The present invention relates to an operation control system for a shredder, which is especially applicable to a rotary type shredder or the like.
2. Description of the Prior Art
A basic structure of a rotary type shredder that is generally used as one of bulky refuse processing apparatuses, is shown in FIG. 16.
In this figure, reference numeral 1 designates a feed conveyor for feeding refuse 20, numeral 2 designates a compression feeder which feeds the refuse 20 to a shredding section 9 while crushing it, and this compression feeder 2 is adapted to be moved vertically by means of an elevator cylinder 5. It is to be noted that although not shown, the compression feeder 2 is rotationally driven by a compression feeder drive motor. In addition, reference numeral 4 designates a push-in device, which is provided for the purpose of pushing the refuse 20 when the refuse 20 cannot be bitten by the compression feeder 2. Reference numeral 6 designates a bar-shaped cutter which is generally called "cutter bar", and reference numeral 7 designates hammers rotating about a point 0, which hammers are rotationally driven by a shredder drive motor (not shown).
Refuse 20 collected by a refuse collecting car or the like is unloaded on the feed conveyor 1, and then it is conveyed to a slide-shaped refuse throw-in section (inlet of a shredding section) 3. The refuse 20 at the refuse throw-in section 3 is fed to a shredding section (shredder main body) 9 while being crushed by the compression feeder 2, and it is shredded by the hammers 7 and the cutter bar 6. A stagnating condition of the refuse 20 at the refuse throw-in section 3 is monitored by means of an ITV camera 11, and an operator controls ON/OFF of the feed conveyor 1, ON/OFF of the compression feeder 2, ON/OFF of the push-in device 4 and UP/DOWN of the elevator cylinder 5 while always watching a screen of a monitor television set.
In a bulky refuse processing apparatus in the prior art, since provision was made such that an operator carried out control for the respective locations while always watching a screen of a monitor television set as described above, a burden upon an operator was large, and in order to mitigate this burden, a demand for automating an operation of a shredder was intense. However, automatically performing acknowledgement of a stagnating condition of refuse, was difficult in an apparatus working under a bad environmental condition such as dust, humidity and impacts as is the case with the above-described shredder, and automation of the operation was prevented due to the aforementioned point acting as a neck.
In addition, the above-described compression feeder 2 in the prior art was operated at a constant peripheral velocity. Consequently, various kinds of refuse 20 were fed to the shredding section 9 at the same speed without differentiating wood not burdening a shredder drive motor from refrigerators, iron scraps and the like heavily burdening a shredder drive motor. Accordingly, there was the problem that in some cases refuse 20 to be shredded was not fed to the shredding section 9 despite of the shredder drive motor having large surplus capacity, but in other cases large-sized refuse 20 acting as a heaving shredding load was fed to the shredding section 9 despite of the shredder drive motor having almost no surplus capacity, and caused tripping of the same drive motor.
Also, a depressing pressure of the above-described compression feeder 2 against the refuse throw-in section 3 must be enlarged as the shredding load is increased because a pulling force into the main body of the shredding section 9 by the hammer 7 becomes strong. However, since the above-described depressing pressure was varied by an operator manipulating an ON/OFF button of a hydraulic valve for the elevator cylinder 5, it was impossible to perform fine control, and therefore, in some case the pulling force into the main body of the shredding section 9 by the hammer 7 became strong and caused the shredder drive motor to trip.
Furthermore, if the depressing pressure against the refuse throw-in section 3 by the above-mentioned compression feeder 2 is excessively enlarged, it may be possible to cause a compression feeder drive motor to trip or stop.